Project1D-electrons coupled to dissipation: a novel approach for understanding and engineering superconducting materials and devices

Researcher (PI)Adrian KANTIAN

Host Institution (HI)UPPSALA UNIVERSITET

Call DetailsStarting Grant (StG), PE3, ERC-2017-STG

SummaryCorrelated electrons are at the forefront of condensed matter theory. Interacting quasi-1D electrons have seen vast progress in analytical and numerical theory, and thus in fundamental understanding and quantitative prediction. Yet, in the 1D limit fluctuations preclude important technological use, particularly of superconductors. In contrast, high-Tc superconductors in 2D/3D are not precluded by fluctuations, but lack a fundamental theory, making prediction and engineering of their properties, a major goal in physics, very difficult. This project aims to combine the advantages of both areas by making major progress in the theory of quasi-1D electrons coupled to an electron bath, in part building on recent breakthroughs (with the PIs extensive involvement) in simulating 1D and 2D electrons with parallelized density matrix renormalization group (pDMRG) numerics. Such theory will fundamentally advance the study of open electron systems, and show how to use 1D materials as elements of new superconducting (SC) devices and materials: 1) It will enable a new state of matter, 1D electrons with true SC order. Fluctuations from the electronic liquid, such as graphene, could also enable nanoscale wires to appear SC at high temperatures. 2) A new approach for the deliberate engineering of a high-Tc superconductor. In 1D, how electrons pair by repulsive interactions is understood and can be predicted. Stabilization by reservoir - formed by a parallel array of many such 1D systems - offers a superconductor for which all factors setting Tc are known and can be optimized. 3) Many existing superconductors with repulsive electron pairing, all presently not understood, can be cast as 1D electrons coupled to a bath. Developing chain-DMFT theory based on pDMRG will allow these materials SC properties to be simulated and understood for the first time. 4) The insights gained will be translated to 2D superconductors to study how they could be enhanced by contact with electronic liquids.

Correlated electrons are at the forefront of condensed matter theory. Interacting quasi-1D electrons have seen vast progress in analytical and numerical theory, and thus in fundamental understanding and quantitative prediction. Yet, in the 1D limit fluctuations preclude important technological use, particularly of superconductors. In contrast, high-Tc superconductors in 2D/3D are not precluded by fluctuations, but lack a fundamental theory, making prediction and engineering of their properties, a major goal in physics, very difficult. This project aims to combine the advantages of both areas by making major progress in the theory of quasi-1D electrons coupled to an electron bath, in part building on recent breakthroughs (with the PIs extensive involvement) in simulating 1D and 2D electrons with parallelized density matrix renormalization group (pDMRG) numerics. Such theory will fundamentally advance the study of open electron systems, and show how to use 1D materials as elements of new superconducting (SC) devices and materials: 1) It will enable a new state of matter, 1D electrons with true SC order. Fluctuations from the electronic liquid, such as graphene, could also enable nanoscale wires to appear SC at high temperatures. 2) A new approach for the deliberate engineering of a high-Tc superconductor. In 1D, how electrons pair by repulsive interactions is understood and can be predicted. Stabilization by reservoir - formed by a parallel array of many such 1D systems - offers a superconductor for which all factors setting Tc are known and can be optimized. 3) Many existing superconductors with repulsive electron pairing, all presently not understood, can be cast as 1D electrons coupled to a bath. Developing chain-DMFT theory based on pDMRG will allow these materials SC properties to be simulated and understood for the first time. 4) The insights gained will be translated to 2D superconductors to study how they could be enhanced by contact with electronic liquids.

Max ERC Funding

1 491 013 €

Duration

Start date: 2018-10-01, End date: 2023-09-30

Project acronym2DMATER

ProjectControlled Synthesis of Two-Dimensional Nanomaterials for Energy Storage and Conversion

Researcher (PI)Xinliang Feng

Host Institution (HI)TECHNISCHE UNIVERSITAET DRESDEN

Call DetailsStarting Grant (StG), PE5, ERC-2012-StG_20111012

Summary"Two-dimensional (2D) nanosheets, which possess a high degree of anisotropy with nanoscale thickness and infinite length in other dimensions, hold enormous promise as a novel class of ultrathin 2D nanomaterials with various unique functionalities and properties, and exhibit great potential in energy storage and conversion systems that are substantially different from their respective 3D bulk forms. Here I propose a strategy for the synthesis and processing of various 2D nanosheets across a broad range of inorganic, organic and polymeric materials with molecular-level or thin thickness through both the top-down exfoliation of layered materials and the bottom-up assembly of available molecular building blocks. Further, I aim to develop the synthesis of various 2D-nanosheet based composite materials with thickness of less than 100 nm and the assembly of 2D nanosheets into novel hierarchal superstrucutures (like aerogels, spheres, porous particles, nanotubes, multi-layer films). The structural features of these 2D nanomaterials will be controllably tailored by both the used layered precursors and processing methodologies. The consequence is that I will apply and combine defined functional components as well as assembly protocols to create novel 2D nanomaterials for specific purposes in energy storage and conversion systems. Their unique characters will include the good electrical conductivity, excellent mechanical flexibility, high surface area, high chemical stability, fast electron transport and ion diffusion etc. Applications will be mainly demonstrated for the construction of lithium ion batteries (anode and cathode), supercapacitors (symmetric and asymmetric) and fuel cells. As the key achievements, I expect to establish the delineation of reliable structure-property relationships and improved device performance of 2D nanomaterials."

"Two-dimensional (2D) nanosheets, which possess a high degree of anisotropy with nanoscale thickness and infinite length in other dimensions, hold enormous promise as a novel class of ultrathin 2D nanomaterials with various unique functionalities and properties, and exhibit great potential in energy storage and conversion systems that are substantially different from their respective 3D bulk forms. Here I propose a strategy for the synthesis and processing of various 2D nanosheets across a broad range of inorganic, organic and polymeric materials with molecular-level or thin thickness through both the top-down exfoliation of layered materials and the bottom-up assembly of available molecular building blocks. Further, I aim to develop the synthesis of various 2D-nanosheet based composite materials with thickness of less than 100 nm and the assembly of 2D nanosheets into novel hierarchal superstrucutures (like aerogels, spheres, porous particles, nanotubes, multi-layer films). The structural features of these 2D nanomaterials will be controllably tailored by both the used layered precursors and processing methodologies. The consequence is that I will apply and combine defined functional components as well as assembly protocols to create novel 2D nanomaterials for specific purposes in energy storage and conversion systems. Their unique characters will include the good electrical conductivity, excellent mechanical flexibility, high surface area, high chemical stability, fast electron transport and ion diffusion etc. Applications will be mainly demonstrated for the construction of lithium ion batteries (anode and cathode), supercapacitors (symmetric and asymmetric) and fuel cells. As the key achievements, I expect to establish the delineation of reliable structure-property relationships and improved device performance of 2D nanomaterials."

SummaryWe propose to develop truly two-dimensional continuous materials and two-dimensional monolayer films composed of individual nanocrystals by the comparatively fast, inexpensive, and scalable colloidal synthesis method. The materials’ properties will be studied in detail, especially regarding their (photo-) electrical transport. This will allow developing new types of device structures, such as Coulomb blockade and field enhancement based transistors.
Recently, we demonstrated the possibility to synthesize in a controlled manner truly two-dimensional colloidal nanostructures. We will investigate their formation mechanism, synthesize further materials as “nanosheets”, develop methodologies to tune their geometrical properties, and study their (photo-) electrical properties.
Furthermore, we will use the Langmuir-Blodgett method to deposit highly ordered monolayers of monodisperse nanoparticles. Such structures show interesting transport properties governed by Coulomb blockade effects known from individual nanoparticles. This leads to semiconductor-like behavior in metal nanoparticle films. The understanding of the electric transport in such “multi-tunnel devices” is still very limited. Thus, we will investigate this concept in detail and take it to its limits. Beside improvement of quality and exchange of material we will tune the nanoparticles’ size and shape in order to gain a deeper understanding of the electrical properties of supercrystallographic assemblies. Furthermore, we will develop device concepts for diode and transistor structures which take into account the novel properties of the low-dimensional assemblies.
Nanosheets and monolayers of nanoparticles truly follow the principle of building devices by the bottom-up approach and allow electric transport measurements in a 2D regime. Highly ordered nanomaterial systems possess easy and reliably to manipulate electronic properties what make them interesting for future (inexpensive) electronic devices.

We propose to develop truly two-dimensional continuous materials and two-dimensional monolayer films composed of individual nanocrystals by the comparatively fast, inexpensive, and scalable colloidal synthesis method. The materials’ properties will be studied in detail, especially regarding their (photo-) electrical transport. This will allow developing new types of device structures, such as Coulomb blockade and field enhancement based transistors.
Recently, we demonstrated the possibility to synthesize in a controlled manner truly two-dimensional colloidal nanostructures. We will investigate their formation mechanism, synthesize further materials as “nanosheets”, develop methodologies to tune their geometrical properties, and study their (photo-) electrical properties.
Furthermore, we will use the Langmuir-Blodgett method to deposit highly ordered monolayers of monodisperse nanoparticles. Such structures show interesting transport properties governed by Coulomb blockade effects known from individual nanoparticles. This leads to semiconductor-like behavior in metal nanoparticle films. The understanding of the electric transport in such “multi-tunnel devices” is still very limited. Thus, we will investigate this concept in detail and take it to its limits. Beside improvement of quality and exchange of material we will tune the nanoparticles’ size and shape in order to gain a deeper understanding of the electrical properties of supercrystallographic assemblies. Furthermore, we will develop device concepts for diode and transistor structures which take into account the novel properties of the low-dimensional assemblies.
Nanosheets and monolayers of nanoparticles truly follow the principle of building devices by the bottom-up approach and allow electric transport measurements in a 2D regime. Highly ordered nanomaterial systems possess easy and reliably to manipulate electronic properties what make them interesting for future (inexpensive) electronic devices.

SummaryThe field of C-H bond activation has evolved at an exponential pace in the last 15 years. What appeals most in those novel synthetic techniques is clear: they bypass the pre-activation steps usually required in traditional cross-coupling chemistry by directly metalating C-H bonds. Many C-H bond functionalizations today however, rely on poorly atom and step efficient oxidants, leading to significant and costly chemical waste, thereby seriously undermining the overall sustainability of those methods. As restrictions in sustainability regulations will further increase, and the cost of certain chemical commodities will rise, atom efficiency in organic synthesis remains a top priority for research.
The aim of 2O2ACTIVATION is to develop novel technologies utilizing O2 as sole terminal oxidant in order to allow useful, extremely sustainable, thermodynamically challenging, dehydrogenative C-N and C-O bond forming coupling reactions. However, the moderate reactivity of O2 towards many catalysts constitutes a major challenge. 2O2ACTIVATION will pioneer the design of new catalysts based on the ultra-simple propene motive, capable of direct activation of O2 for C-H activation based cross-couplings. The project is divided into 3 major lines: O2 activation using propene and its analogues (propenoids), 1) without metal or halide, 2) with hypervalent halide catalysis, 3) with metal catalyzed C-H activation.
The philosophy of 2O2ACTIVATION is to focus C-H functionalization method development on the oxidative event.
Consequently, 2O2ACTIVATION breakthroughs will dramatically shortcut synthetic routes through the use of inactivated, unprotected, and readily available building blocks; and thus should be easily scalable. This will lead to a strong decrease in the costs related to the production of many essential chemicals, while preserving the environment (water as terminal by-product). The resulting novels coupling methods will thus have a lasting impact on the chemical industry.

The field of C-H bond activation has evolved at an exponential pace in the last 15 years. What appeals most in those novel synthetic techniques is clear: they bypass the pre-activation steps usually required in traditional cross-coupling chemistry by directly metalating C-H bonds. Many C-H bond functionalizations today however, rely on poorly atom and step efficient oxidants, leading to significant and costly chemical waste, thereby seriously undermining the overall sustainability of those methods. As restrictions in sustainability regulations will further increase, and the cost of certain chemical commodities will rise, atom efficiency in organic synthesis remains a top priority for research.
The aim of 2O2ACTIVATION is to develop novel technologies utilizing O2 as sole terminal oxidant in order to allow useful, extremely sustainable, thermodynamically challenging, dehydrogenative C-N and C-O bond forming coupling reactions. However, the moderate reactivity of O2 towards many catalysts constitutes a major challenge. 2O2ACTIVATION will pioneer the design of new catalysts based on the ultra-simple propene motive, capable of direct activation of O2 for C-H activation based cross-couplings. The project is divided into 3 major lines: O2 activation using propene and its analogues (propenoids), 1) without metal or halide, 2) with hypervalent halide catalysis, 3) with metal catalyzed C-H activation.
The philosophy of 2O2ACTIVATION is to focus C-H functionalization method development on the oxidative event.
Consequently, 2O2ACTIVATION breakthroughs will dramatically shortcut synthetic routes through the use of inactivated, unprotected, and readily available building blocks; and thus should be easily scalable. This will lead to a strong decrease in the costs related to the production of many essential chemicals, while preserving the environment (water as terminal by-product). The resulting novels coupling methods will thus have a lasting impact on the chemical industry.

Max ERC Funding

1 489 823 €

Duration

Start date: 2017-03-01, End date: 2022-02-28

Project acronym3DWATERWAVES

ProjectMathematical aspects of three-dimensional water waves with vorticity

Researcher (PI)Erik Torsten Wahlén

Host Institution (HI)LUNDS UNIVERSITET

Call DetailsStarting Grant (StG), PE1, ERC-2015-STG

SummaryThe goal of this project is to develop a mathematical theory for steady three-dimensional water waves with vorticity. The mathematical model consists of the incompressible Euler equations with a free surface, and vorticity is important for modelling the interaction of surface waves with non-uniform currents. In the two-dimensional case, there has been a lot of progress on water waves with vorticity in the last decade. This progress has mainly been based on the stream function formulation, in which the problem is reformulated as a nonlinear elliptic free boundary problem. An analogue of this formulation is not available in three dimensions, and the theory has therefore so far been restricted to irrotational flow. In this project we seek to go beyond this restriction using two different approaches. In the first approach we will adapt methods which have been used to construct three-dimensional ideal flows with vorticity in domains with a fixed boundary to the free boundary context (for example Beltrami flows). In the second approach we will develop methods which are new even in the case of a fixed boundary, by performing a detailed study of the structure of the equations close to a given shear flow using ideas from infinite-dimensional bifurcation theory. This involves handling infinitely many resonances.

The goal of this project is to develop a mathematical theory for steady three-dimensional water waves with vorticity. The mathematical model consists of the incompressible Euler equations with a free surface, and vorticity is important for modelling the interaction of surface waves with non-uniform currents. In the two-dimensional case, there has been a lot of progress on water waves with vorticity in the last decade. This progress has mainly been based on the stream function formulation, in which the problem is reformulated as a nonlinear elliptic free boundary problem. An analogue of this formulation is not available in three dimensions, and the theory has therefore so far been restricted to irrotational flow. In this project we seek to go beyond this restriction using two different approaches. In the first approach we will adapt methods which have been used to construct three-dimensional ideal flows with vorticity in domains with a fixed boundary to the free boundary context (for example Beltrami flows). In the second approach we will develop methods which are new even in the case of a fixed boundary, by performing a detailed study of the structure of the equations close to a given shear flow using ideas from infinite-dimensional bifurcation theory. This involves handling infinitely many resonances.

Max ERC Funding

1 203 627 €

Duration

Start date: 2016-03-01, End date: 2021-02-28

Project acronym3FLEX

ProjectThree-Component Fermi Gas Lattice Experiment

Researcher (PI)Selim Jochim

Host Institution (HI)RUPRECHT-KARLS-UNIVERSITAET HEIDELBERG

Call DetailsStarting Grant (StG), PE2, ERC-2011-StG_20101014

SummaryUnderstanding the many-body physics of strongly correlated systems has always been a major challenge for theoretical and experimental physics. The recent advances in the field of ultracold quantum gases have opened a completely new way to study such strongly correlated systems. It is now feasible to use ultracold gases as quantum simulators for such diverse systems such as the Hubbard model or the BCS-BEC crossover. The objective of this project is to study a three-component Fermi gas in an optical lattice, a system with rich many-body physics. With our experiments we aim to contribute to the understanding of exotic phases which are discussed in the context of QCD and condensed matter physics.

Understanding the many-body physics of strongly correlated systems has always been a major challenge for theoretical and experimental physics. The recent advances in the field of ultracold quantum gases have opened a completely new way to study such strongly correlated systems. It is now feasible to use ultracold gases as quantum simulators for such diverse systems such as the Hubbard model or the BCS-BEC crossover. The objective of this project is to study a three-component Fermi gas in an optical lattice, a system with rich many-body physics. With our experiments we aim to contribute to the understanding of exotic phases which are discussed in the context of QCD and condensed matter physics.

SummaryCrucial processes within cells depend on specific non-covalent interactions which mediate the assembly of proteins and other biomolecules. Deriving structural information to understand the function of these complex systems is the primary goal of Structural Biology.
In this application, the recently developed LILBID method (Laser Induced Liquid Bead Ion Desorption) will be optimized for investigation of macromolecular complexes with a mass accuracy two orders of magnitude better than in 1st generation spectrometers.
Controlled disassembly of the multiprotein complexes in the mass spectrometric analysis while keeping the 3D structure intact, will allow for the determination of complex stoichiometry and connectivity of the constituting proteins. Methods for such controlled disassembly will be developed in two separate units of the proposed LILBID spectrometer, in a collision chamber and in a laser dissociation chamber, enabling gas phase dissociation of protein complexes and removal of excess water/buffer molecules. As a third unit, a chamber allowing determination of ion mobility (IM) will be integrated to determine collisional cross sections (CCS). From CCS, unique information regarding the spatial arrangement of proteins in complexes or subcomplexes will then be obtainable from LILBID.
The proposed design of the new spectrometer will offer fundamentally new possibilities for the investigation of non-covalent RNA, soluble and membrane protein complexes, as well as broadening the applicability of non-covalent MS towards supercomplexes.

Crucial processes within cells depend on specific non-covalent interactions which mediate the assembly of proteins and other biomolecules. Deriving structural information to understand the function of these complex systems is the primary goal of Structural Biology.
In this application, the recently developed LILBID method (Laser Induced Liquid Bead Ion Desorption) will be optimized for investigation of macromolecular complexes with a mass accuracy two orders of magnitude better than in 1st generation spectrometers.
Controlled disassembly of the multiprotein complexes in the mass spectrometric analysis while keeping the 3D structure intact, will allow for the determination of complex stoichiometry and connectivity of the constituting proteins. Methods for such controlled disassembly will be developed in two separate units of the proposed LILBID spectrometer, in a collision chamber and in a laser dissociation chamber, enabling gas phase dissociation of protein complexes and removal of excess water/buffer molecules. As a third unit, a chamber allowing determination of ion mobility (IM) will be integrated to determine collisional cross sections (CCS). From CCS, unique information regarding the spatial arrangement of proteins in complexes or subcomplexes will then be obtainable from LILBID.
The proposed design of the new spectrometer will offer fundamentally new possibilities for the investigation of non-covalent RNA, soluble and membrane protein complexes, as well as broadening the applicability of non-covalent MS towards supercomplexes.

Max ERC Funding

1 264 477 €

Duration

Start date: 2014-02-01, End date: 2019-01-31

Project acronymACDC

ProjectAlgorithms and Complexity of Highly Decentralized Computations

Researcher (PI)Fabian Daniel Kuhn

Host Institution (HI)ALBERT-LUDWIGS-UNIVERSITAET FREIBURG

Call DetailsStarting Grant (StG), PE6, ERC-2013-StG

Summary"Many of today's and tomorrow's computer systems are built on top of large-scale networks such as, e.g., the Internet, the world wide web, wireless ad hoc and sensor networks, or peer-to-peer networks. Driven by technological advances, new kinds of networks and applications have become possible and we can safely assume that this trend is going to continue. Often modern systems are envisioned to consist of a potentially large number of individual components that are organized in a completely decentralized way. There is no central authority that controls the topology of the network, how nodes join or leave the system, or in which way nodes communicate with each other. Also, many future distributed applications will be built using wireless devices that communicate via radio.
The general objective of the proposed project is to improve our understanding of the algorithmic and theoretical foundations of decentralized distributed systems. From an algorithmic point of view, decentralized networks and computations pose a number of fascinating and unique challenges that are not present in sequential or more standard distributed systems. As communication is limited and mostly between nearby nodes, each node of a large network can only maintain a very restricted view of the global state of the system. This is particularly true if the network can change dynamically, either by nodes joining or leaving the system or if the topology changes over time, e.g., because of the mobility of the devices in case of a wireless network. Nevertheless, the nodes of a network need to coordinate in order to achieve some global goal.
In particular, we plan to study algorithms and lower bounds for basic computation and information dissemination tasks in such systems. In addition, we are particularly interested in the complexity of distributed computations in dynamic and wireless networks."

"Many of today's and tomorrow's computer systems are built on top of large-scale networks such as, e.g., the Internet, the world wide web, wireless ad hoc and sensor networks, or peer-to-peer networks. Driven by technological advances, new kinds of networks and applications have become possible and we can safely assume that this trend is going to continue. Often modern systems are envisioned to consist of a potentially large number of individual components that are organized in a completely decentralized way. There is no central authority that controls the topology of the network, how nodes join or leave the system, or in which way nodes communicate with each other. Also, many future distributed applications will be built using wireless devices that communicate via radio.
The general objective of the proposed project is to improve our understanding of the algorithmic and theoretical foundations of decentralized distributed systems. From an algorithmic point of view, decentralized networks and computations pose a number of fascinating and unique challenges that are not present in sequential or more standard distributed systems. As communication is limited and mostly between nearby nodes, each node of a large network can only maintain a very restricted view of the global state of the system. This is particularly true if the network can change dynamically, either by nodes joining or leaving the system or if the topology changes over time, e.g., because of the mobility of the devices in case of a wireless network. Nevertheless, the nodes of a network need to coordinate in order to achieve some global goal.
In particular, we plan to study algorithms and lower bounds for basic computation and information dissemination tasks in such systems. In addition, we are particularly interested in the complexity of distributed computations in dynamic and wireless networks."

SummaryNew insight into ever smaller microscopic units of matter as well as in ever faster evolving chemical, physical or atomic processes pushes the frontiers in many fields in science. Pump/probe experiments turned out to be the most direct approach to time-domain investigations of fast-evolving microscopic processes. Accessing atomic and molecular inner-shell processes directly in the time-domain requires a combination of short wavelengths in the few hundred eV range and sub-femtosecond pulse duration. The concept of light-field-controlled XUV photoemission employs an XUV pulse achieved by High-order Harmonic Generation (HHG) as a pump and the light pulse as a probe or vice versa. The basic prerequisite, namely the generation and measurement of isolated sub-femtosecond XUV pulses synchronized to a strong few-cycle light pulse with attosecond precision, opens up a route to time-resolved inner-shell atomic and molecular spectroscopy with present day sources. Studies of attosecond electronic motion (1 as = 10-18 s) in solids and on surfaces and interfaces have until now remained out of reach. The unprecedented time resolution of the aforementioned technique will enable for the first time monitoring of sub-fs dynamics of such systems in the time domain. These dynamics – of electronic excitation, relaxation, and wave packet motion – are of broad scientific interest and pertinent to the development of many modern technologies including semiconductor and molecular electronics, optoelectronics, information processing, photovoltaics, and optical nano-structuring. The purpose of this project is to investigate phenomena like the temporal evolution of direct photoemission, interference effects in resonant photoemission, fast adsorbate-substrate charge transfer, and electronic dynamics in supramolecular assemblies, in a series of experiments in order to overcome the temporal limits of measurements in solid state physics and to better understand processes in microcosm.

New insight into ever smaller microscopic units of matter as well as in ever faster evolving chemical, physical or atomic processes pushes the frontiers in many fields in science. Pump/probe experiments turned out to be the most direct approach to time-domain investigations of fast-evolving microscopic processes. Accessing atomic and molecular inner-shell processes directly in the time-domain requires a combination of short wavelengths in the few hundred eV range and sub-femtosecond pulse duration. The concept of light-field-controlled XUV photoemission employs an XUV pulse achieved by High-order Harmonic Generation (HHG) as a pump and the light pulse as a probe or vice versa. The basic prerequisite, namely the generation and measurement of isolated sub-femtosecond XUV pulses synchronized to a strong few-cycle light pulse with attosecond precision, opens up a route to time-resolved inner-shell atomic and molecular spectroscopy with present day sources. Studies of attosecond electronic motion (1 as = 10-18 s) in solids and on surfaces and interfaces have until now remained out of reach. The unprecedented time resolution of the aforementioned technique will enable for the first time monitoring of sub-fs dynamics of such systems in the time domain. These dynamics – of electronic excitation, relaxation, and wave packet motion – are of broad scientific interest and pertinent to the development of many modern technologies including semiconductor and molecular electronics, optoelectronics, information processing, photovoltaics, and optical nano-structuring. The purpose of this project is to investigate phenomena like the temporal evolution of direct photoemission, interference effects in resonant photoemission, fast adsorbate-substrate charge transfer, and electronic dynamics in supramolecular assemblies, in a series of experiments in order to overcome the temporal limits of measurements in solid state physics and to better understand processes in microcosm.

SummaryThe rise of atmospheric O2 ~2,500 million years ago is one of the most profound transitions in Earth's history. Yet, despite its central role in shaping Earth's surface environment, the cause for the rise of O2 remains poorly understood. Tight coupling between the O2 cycle and the biogeochemical cycles of redox-active elements, such as C, Fe and S, implies radical changes in these cycles before, during and after the rise of O2. These changes, too, are incompletely understood, but have left valuable information encoded in the geological record. This information has been qualitatively interpreted, leaving many aspects of the rise of O2, including its causes and constraints on ocean chemistry before and after it, topics of ongoing research and debate. Here, I outline a research program to address this fundamental question in geochemical Earth systems evolution. The inherently interdisciplinary program uniquely integrates laboratory experiments, numerical models, geological observations, and geochemical analyses. Laboratory experiments and geological observations will constrain unknown parameters of the early biogeochemical cycles, and, in combination with field studies, will validate and refine the use of paleoenvironmental proxies. The insight gained will be used to develop detailed models of the coupled biogeochemical cycles, which will themselves be used to quantitatively understand the events surrounding the rise of O2, and to illuminate the dynamics of elemental cycles in the early oceans.
This program is expected to yield novel, quantitative insight into these important events in Earth history and to have a major impact on our understanding of early ocean chemistry and the rise of O2. An ERC Starting Grant will enable me to use the excellent experimental and computational facilities at my disposal, to access the outstanding human resource at the Weizmann Institute of Science, and to address one of the major open questions in modern geochemistry.

The rise of atmospheric O2 ~2,500 million years ago is one of the most profound transitions in Earth's history. Yet, despite its central role in shaping Earth's surface environment, the cause for the rise of O2 remains poorly understood. Tight coupling between the O2 cycle and the biogeochemical cycles of redox-active elements, such as C, Fe and S, implies radical changes in these cycles before, during and after the rise of O2. These changes, too, are incompletely understood, but have left valuable information encoded in the geological record. This information has been qualitatively interpreted, leaving many aspects of the rise of O2, including its causes and constraints on ocean chemistry before and after it, topics of ongoing research and debate. Here, I outline a research program to address this fundamental question in geochemical Earth systems evolution. The inherently interdisciplinary program uniquely integrates laboratory experiments, numerical models, geological observations, and geochemical analyses. Laboratory experiments and geological observations will constrain unknown parameters of the early biogeochemical cycles, and, in combination with field studies, will validate and refine the use of paleoenvironmental proxies. The insight gained will be used to develop detailed models of the coupled biogeochemical cycles, which will themselves be used to quantitatively understand the events surrounding the rise of O2, and to illuminate the dynamics of elemental cycles in the early oceans.
This program is expected to yield novel, quantitative insight into these important events in Earth history and to have a major impact on our understanding of early ocean chemistry and the rise of O2. An ERC Starting Grant will enable me to use the excellent experimental and computational facilities at my disposal, to access the outstanding human resource at the Weizmann Institute of Science, and to address one of the major open questions in modern geochemistry.